Use of CBD products has tripled in the past year. We look at the evidence supporting the health claims.
By Nikki-Lee Birdsey
Health claims ranging from easing anxiety to relieving pain are used to promote CBD products, a form of medicinal cannabis. Last year, 21,452 products were supplied to Kiwis, up from 6993 in 2019. So, what is CBD, will it get you high, and what does the research say about its benefits?
What is CBD?
CBD, or cannabidiol, is a chemical compound found in cannabis plants. You won’t get high on CBD products. That’s because the tetrahydrocannabinol (THC) – the compound in cannabis that delivers the high – is low. Rules restrict the amount of THC and other specified substances to no more than two percent of the total CBD.
CBD oil products contain concentrated CBD. They typically come in oral drops or capsules.
Both CBD and THC interact with the body’s endocannabinoid system. There is more to be learned about this system, but research has found it affects various functions including mood, appetite, movement and the immune system.
Can I buy it here?
CBD products are classified as prescription medicines. So you’ll need a prescription from your doctor. You can’t get more than a three-month supply at one time.
Most medicinal cannabis-based products are “unapproved medicines” (except for a drug called Sativex, which contains both CBD and THC, and is used to treat multiple sclerosis symptoms such as muscle spasms). The Medicines Act allows doctors to prescribe unapproved medicines – drugs that haven’t been vetted by Medsafe – provided rules for supply are followed.
The Medicinal Cannabis Agency, part of the Ministry of Health, is responsible for assessing medicinal cannabis products, including CBD, to make sure they meet a minimum quality standard. Products that meet the standard can be prescribed by a doctor.
Suppliers have until 30 September 2021 to get their products assessed. So far, two CBD products have been ticked off against the standard.
A doctor can prescribe a CBD product that hasn’t met the quality standard, but the prescription has to be for a named patient. The doctor must import the CBD product themselves or get a pharmacy to import it on their behalf.
Can I buy it overseas?
Instagram ads touting CBD oil-infused chocolate from the US may flicker across your social media feed. But you can’t just click on an ad for a CBD product and then have it shipped here. Because these products are prescription medicines, you typically have to buy them from your doctor or a pharmacy.
There are more relaxed rules for CBD in other countries.
For example, it’s legal in many US states to buy CBD without a prescription. In Australia, pharmacies can supply low-dose CBD over-the-counter, although products must be approved by the medicines regulator.
What does it cost?
Prices for CBD products vary depending on where you take your prescription and what you’re getting.
Prices we found listed on clinic websites ranged from $60 (750mg of CBD) to $400 (4500mg). You also need to factor in the cost of your doctor’s appointment.
What the science says
Scientific research on the effectiveness of CBD to treat medical conditions is in its early stages. There’s some clinical evidence CBD, by itself, may be effective in treating epilepsy, psychosis, anxiety, and movement disorders such as multiple sclerosis.
However, this evidence isn’t considered strong.
In many cases, trials were small or had mixed results. Adverse side effects, such as nausea and diarrhoea, have been reported in some studies. No studies have assessed the long-term negative effects of medicinal cannabis-based products.
Professor Michelle Glass, University of Otago Department of Pharmacology and Toxicology head, said “there’s a wealth of claims on websites that are not grounded in research or there’s very little research to back them up.
“Given what you’re spending, you’re actually nowhere near what’s considered a therapeutic dose.”
Prof Glass said there’s clinical trial evidence for paediatric seizure disorders that show CBD is very effective in pure, pharmaceutical-grade high doses (600mg per day).
Is CBD addictive? Prof Glass said “there’s nothing to suggest it is”.
Here’s the state of evidence for using CBD to treat certain conditions.
There’s a lack of good evidence that CBD reduces anxiety and more research is needed. While there have been many studies, they’ve had small sample sizes. In 2011, for example, a study involving 24 participants found CBD more effective than placebo for reducing anxiety associated with public speaking.
It’s uncertain if CBD can help ease inflammation or inflammatory conditions. A 2020 review of CBD as a possible treatment for arthritis and other joint diseases found a lack of high-quality evidence.
Two reviews, conducted in 2018 by the Cochrane Collaboration, studied the effect of cannabis and CBD on two illnesses that cause severe inflammation: ulcerative colitis and Crohn’s disease. The authors found the evidence inconclusive and more research was needed.
There’s no good quality evidence showing CBD reduces insomnia. Research shows drugs containing both CBD and THC improve sleep in the short term for people with some conditions, such as sleep apnoea.
There’s evidence cannabinoids may be effective for chronic pain, but studies rarely involved CBD alone. A 2019 review, published in The Journal of Clinical Pharmacology, found just three small trials assessing CBD alone in treating pain. The results were inconclusive.
A 2018 review by the Cochrane Collaboration found no high-quality evidence that any cannabis-derived product, including CBD, helps chronic neuropathic pain (arising from damaged nerves).
There is evidence for the use of highly concentrated CBD to help treat two forms of child-onset severe epilepsy – Lennox-Gastaut syndrome and Dravet syndrome. In 2018, the US Food and Drug Administration approved a CBD medicine, Epidiolex, to treat seizures related to these syndromes.